120 research outputs found

    The Role of the Direct Normal Irradiance (DNI) Forecasting in the Operation of Solar Concentrating Plants

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    Abstract A method capable of forecasting the DHI (Diffuse Horizontal Irradiance), DNI (Direct Normal Irradiance) and GHI (Global Horizontal Irradiance) for targeted locations involved in the installation of concentrating solar plants has been developed at the Casaccia Center of the ENEA located near Rome (Italy). These forecasts are issued daily at 00:00 in the morning and cover a temporal arc of four days which includes the actual day as well as the following three days in hourly time resolution. The method develops and expands upon information taken from Internet and these forecasts are presented as an example on the Internet site for five localities of ENEA interest: http://www.solaritaly.enea.it/Previsioni/PrevisioniEn.php; they are potentially available for every location. The RMSE% of the DNI forecasts on daily basis compared with the measures is 10%. In the Internet age, old methods must be updated to take into account the immense potential available today on the net

    A Fiat-Shamir Implementation Note

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    In the Micali-Shamir paper improving the efficiency of the original Fiat-Shamir protocol, the authors state that (...) not all of the viv_i\u27s will be quadratic residues mod nn. We overcome this technical difficulty with an appropriate perturbation technique (...) This perturbation technique is made more explicit in the associated patent application: Each entity is allowed to modify the standard vjv_j which are QNRs. A particularly simple way to achieve this is to pick a modulus n=pqn=pq where p=3 mod 8p=3 \bmod 8 and q=7 mod 8q=7 \bmod 8, since then exactly one of vj,−vj,2vj,−2vjv_j,-v_j,2v_j,-2v_j is a QR mod nn for any vjv_j. The appropriate variant of each vjv_j can be (...) deduced by the verifier himself during the verification of given signatures. In this short note we clarify the way in which the verifier can infer by himself the appropriate variant of each vjv_j during verification

    Anti-microbial Use in Animals: How to Assess the Trade-offs

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    Antimicrobials are widely used in preventive and curative medicine in animals. Benefits from curative use are clear – it allows sick animals to be healthy with a gain in human welfare. The case for preventive use of antimicrobials is less clear cut with debates on the value of antimicrobials as growth promoters in the intensive livestock industries. The possible benefits from the use of antimicrobials need to be balanced against their cost and the increased risk of emergence of resistance due to their use in animals. The study examines the importance of animals in society and how the role and management of animals is changing including the use of antimicrobials. It proposes an economic framework to assess the trade-offs of anti-microbial use and examines the current level of data collection and analysis of these trade-offs. An exploratory review identifies a number of weaknesses. Rarely are we consistent in the frameworks applied to the economic assessment anti-microbial use in animals, which may well be due to gaps in data or the prejudices of the analysts. There is a need for more careful data collection that would allow information on (i) which species and production systems antimicrobials are used in, (ii) what active substance of antimicrobials and the application method and (iii) what dosage rates. The species need to include companion animals as well as the farmed animals as it is still not known how important direct versus indirect spread of resistance to humans is. In addition, research is needed on pricing antimicrobials used in animals to ensure that prices reflect production and marketing costs, the fixed costs of anti-microbial development and the externalities of resistance emergence. Overall, much work is needed to provide greater guidance to policy, and such work should be informed by rigorous data collection and analysis systems

    Thrifty Zero-Knowledge - When Linear Programming Meets Cryptography

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    We introduce “thrifty” zero-knowledge protocols, or TZK. These protocols are constructed by introducing a bias in the challenge send by the prover. This bias is chosen so as to maximize the security versus effort trade-off. We illustrate the benefits of this approach on several well-known zero-knowledge protocols

    Sources of antibiotic resistance: zoonotic, human, environment

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    Antibiotic resistance is a global problem that must be managed under the One Health perspective. Retrospectively, it is assumed that microbial populations able to cope with compounds with antimicrobial activity and susceptible bacteria lived in equilibrium for a thousand years. This situation would change in the middle 1940s of the twentieth century when one of the most important revolutions of modern medicine started - the use of a natural antimicrobial compound, the penicillin, to treat infectious bacterial diseases. Over the years, the massive use of antibiotics in human and animal medicine, as well as in animal production for both growth promotion and infection prophylaxis/metaphylaxis, accelerated and shaped one of the most successful evolutionary case studies. As a result of an impressive combination of genome and community dynamics, bacteria with acquired antibiotic resistance are nowadays widespread across different environmental compartments (water, soil, wildlife) as well as in the human food chain (poultry, livestock, aquaculture, produce). Hence, the evolutionary success of these bacteria turned to represent a major threat to the human health. This review discusses some of the drivers and paths of antibiotic resistance dissemination across zoonotic, human, and environmental sources.info:eu-repo/semantics/acceptedVersio

    The path of least resistance: Paying for antibiotics in non-human uses

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    Antibiotic resistance is a critical threat to human and animal health. Despite the importance of antibiotics, regulators continue to allow antibiotics to be used in low-value applications - subtherapeutic dosing in animals, and spraying tobacco plants for blue mold, for example - where the benefits are unlikely to outweigh the costs in terms of increased resistance. We explore the application of a user fee in non-human uses of antibiotics. Such a fee would efficiently deter low value uses while also providing funding to support the development of the urgently needed new antibiotics

    Public-Key Based Lightweight Swarm Authentication

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    We describe a lightweight algorithm performing whole-network authentication in a distributed way. This protocol is more efficient than one-to-one node authentication: it results in less communication, less computation, and overall lower energy consumption. The proposed algorithm is provably secure, and achieves zero-knowledge authentication of a network in a time logarithmic in the number of nodes

    Solar Radiation Maps

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    [EN]Solar maps are very interesting tools to describe the characteristics of a region from the solar radiation point of view, and can be applied in atmospheric sciences and for energy engineering. To make them possible, a solar radiation numerical model is proposed. This one allows us to estimate radiation values on any point on earth. The model takes into account the terrain surface conditions and the cast shadows. The procedure uses 2-D adaptive triangles meshes built refining according to surface and albedo characteristics. Solar irradiance values are obtained for clear sky conditions. Using clear sky index as a conversion factor, real sky values are computed in terms of irradiance or irradiation with a desired time step. Finally, the solar radiation maps are obtained for all the domain

    Boosting OMD for Almost Free Authentication of Associated Data

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    We propose pure OMD (p-OMD) as a new variant of the Offset Merkle-DamgĂ„rd (OMD) authenticated encryption scheme. Our new scheme inherits all desirable security features of OMD while having a more compact structure and providing higher efficiency. The original OMD scheme, as submitted to the CAESAR competition, couples a single pass of a variant of the Merkle-DamgĂ„rd (MD) iteration with the counter-based XOR MAC algorithm to provide privacy and authenticity. Our improved p-OMD scheme dispenses with the XOR MAC algorithm and is purely based on the MD iteration; hence, the name ``pure'' OMD. To process a message of ℓ\ell blocks and associated data of aa blocks, OMD needs ℓ+a+2\ell+a+2 calls to the compression function while p-OMD only requires max{ℓ,a\ell, a}+22 calls. Therefore, for a typical case where ℓ≄a\ell \geq a, p-OMD makes just ℓ+2\ell+2 calls to the compression function; that is, associated data is processed almost freely compared to OMD. We prove the security of p-OMD under the same standard assumption (pseudo-randomness of the compression function) as made in OMD; moreover, the security bound for p-OMD is the same as that of OMD, showing that the modifications made to boost the performance are without any loss of security
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